Influence of gas mixtures Ar-He and Ar-He-O₂ on weldability of aluminum alloy AA5083-O using automated GMAW-P

Abstract

Problems of industries and manufacturers of welded structures in aluminium alloys are centred on reduction of mechanical properties in welded joints due to heat input effects on the heat affected zone; as well as effects of discontinuities and metallurgical defects, high cost repairs, and low productivity. The aim of this paper is to evaluate the influence of gas mixtures 80Ar20He (MG1), 60Ar40He (MG2), 80Ar19He1O₂ (MG3), and 60Ar39He1O₂ (MG4), on aluminium alloy AA5083-O weldability using filler metal ER5183 using the automated GMAW-P process. Methodology has included a factorial experiment design, customisation of welding parameters, and characterisation of base metal and welding regions. Analysis of results were carried out based on microstructure evaluation of welding regions, measurements of hardness and tensile properties, observations of discontinuities and defects, costs evaluation, and welding speed. Results show that gas mixtures with O₂ are highly beneficial to obtain good weldability of the studied alloy.

Keywords:

• Weldability and stability
• aluminium alloys for naval applications
• welded microstructure
• mechanical properties
• integrity welding

Acknowledgements

The authors would like to thank the University of the North, the Autonomous University of the Caribbean, the company COTECMAR, SENA Colombo-German National Centre and CNPEM/ABTLuS and its Nanotechnology National Laboratory – LLNano in Campinas, Brazil, for the financial and logistic support with the project. They would also like to thank the individuals José Alfredo Morales, José David Quintero, Milena Ortega and Edinson Samaca from Cotecmar for the logistic support in this phase of the project. Thanks to the students of Mechanical Engineering at the Autonomous University of the Caribbean: Halley Vásquez and Julio Loaiza, for their support during the microstructural characterisation.